In the field of microfabrication represented by fabrication of integrated circuit devices, the design rules have become more and more minute in order to achieve higher integration. Development of a lithographic process enabling microfabrication in a stable manner has been actively pursued.
In order to satisfy such a demand, various radiation-sensitive resin compositions for chemically amplified resists have been developed. In such a lithographic process, foreign matter in the radiation-sensitive resin composition which could have been disregarded in the past is now found to cause development defects and reduce the yield of semiconductor devices as an increased demand for miniaturization has been raised.
In order to overcome this problem, filtering methods to remove foreign matter in radiation-sensitive resin compositions have been proposed (for example, Patent Documents 1 to 4).    [Patent Document 1] JP-A-2002-311600    [Patent Document 2] JP-A-2002-311601    [Patent Document 3] JP-A-2004-53887    [Patent Document 4] JP-A-2004-195427